David: Neuropsychologists are like neurologists who focus on the neurologic affects of diseases like PD on emotions, cognition and behavior. Dopamine decreases and deterioration of brain cells (substantia nigra, which produce dopamine) are neurologic (i.e, physical) changes that not only affect motor function (i.e., gait, mobility), but also effect thinking, memory, emotions, etc. Neuropsychologists are the ones who help measure and treat the cognitive, emotional and behavioral changes caused by neurologic disorders. Importantly, they do not treat psychiatric disorders, or disorders of mental health. They treat the emotional consequences of physical disorders. They use behavioral methods, and not drugs, to help compensate for, get around, and improve the negative changes in thinking, emotions, behavior, including fatigue, sleep, etc. Unlike psychologists, who treat abnormal behavior due to psychiatric problems, neuropsychologists treat brain based behavior disorders. We treat persons with Brain Injuries, Stroke, Parkinson's, Multiple Sclerosis, Epilepsy, and so on. -- ----------------------------------------------------- Michael F. Martelli, Ph.D. Director, Rehabilitation Neuropsychology Concussion Care Centre of Virginia 10120 West Broad Street, Suites G & H Glen Allen, VA 23060 Phone: 804-747-8429 Cell: 804-399-5433 Fax: 804-346-1956 Email: [log in to unmask] Villa Martelli Disability Resources Webpage: http://go.to/MFMartelliPhD A smooth sea never made a skilled mariner. -- English proverb